Color yielding elements for color photography



Q. W. MURRAY 295416,40@

coLoE YIELDING ELEMENT EoR coLoR PHOTOGRAPHY Filed Dec. 11, 1945 March 279 3.9M

and Mage/Zta Colm brlzef Methyl Cellulose a/zd/fqgezzta Calofl'brmer Gelatin-Silver/alde Transparent Supparf Sodiumlginate alpha-Naplgflzol Gelatin-Svefzlzlde argta Coated Papel" Cella lose .ceta te P/ztluz late-Blue Green CaIarfr/fler Gelatin, .Silverffaz'de Wanspar'ent Support Willi/735m 1'='0yvin z/Z.AI cetal Magenta ColorFor/lzer Hydr'oyzed UnyZcetate/Etkg/Zene film ATTORNEY Patented Mar. '27, 1951 UNITED STATES PATENT YOFFICE coto-R YIELDINQELEMENgrs Foa comit PHOTOGRAPHY Otis Willard Murray, Fords, N. J., assigner to I; du Pont de Nemours &' Company, Wilmington, Del., a corporation of Delaware Application December 11, 1945, Serial N o. 634,256

11 Claims.

This invention relates to photography and more particularly to color-yielding elements' for color photography. yStill more particularly it relates to multilayerfilms for color photography. Still more particularly itrelate's to photographic films which have two' differentially sensitized silver halide emulsion layers and two respectively coactive adjacent layers containing color formers, said layers being removable in aqueous baths. The invention also relates to the preparation of such elements and to processes for the production of dye images therefrom.

A relatively large number of processes for producing multicolor` images Which involve the use of color formers have been proposed. The color formers couple with the oxidation products of primary aromatic amino color developing agents, e. g., diethylparaphenylene diamine hydrochloride and 2-amino-5-diethylam`ino toluene hydrochloride, formed during the development of silver salt images and produce quinoneimine or azomethine dye images in situ with the silver salt images, After removal of the latter, a dye image remains. Films for three-color photography, for example, have been proposed which contain a plurality of silver halide emulsion layers and iilter layers which contain immobile color formers and are so arranged and sensitized that each will record about one-third of the visible spectrum.

Another type has been proposed which instead of having the color formers in the silver halide emulsion layers have them in adjacent Waterpermeable colloid emulsion layers.

Each of the above types sulier from some disadvantages. When color iormers are placed in emulsion layers they often reduce the overall sensitivity, reduce or destroy the color sensitized characteristics, and/or produce general emulsion fog. This is particularly true of the high molecular Weight, non-migratory type. Others wander in emulsion layers and cause dilution and contamination of color. These disadvantages are overcome when color formers are placed in adjacent layers. The resulting films, however, sometime do not have an adequate density of dye image or dye image-contrast when immobile color formers are used. When the mobile types are used in continuous pro^essing systems, e. g., of cine film, an accumulation of leached color former obtains in the developing solution which gives rise to color contamination in the layers.

The above objects may be accomplished and the above disadvantages obviated by the novel coloryielding elements and processes of this invention. It hasA been found that-if color formers which migrate in gelatino-silver halide emulsions' are incorporated in a Water-soluble, dilute alkali-iti# soluble colloid and coated on a gelatine-Silver halide emulsion layer, useful color-yielding elements are obtained. The colloids should be substantially insoluble in aqueous alkalinev developer solutions containing 2% or more by weight of dissolved inorganic salts. A-ll of the advantagesgained by the use ofl color fo'rrnersin adjacent layers are obtained. 'In addition, the elements have other decided advantages. During color coupling development the color formers migrate to the adjacent silver halide grains andforrn dye images in situ with the developed silver images instead of in the adjacent colloid layers. Any color former which is not utilized during color coupling development can readily be removed from the film by Washing the layer of Water'`` soluble, dilute alkali-inseluble colloid from the element. This can be accomplished by Washing with Water immediately after development. The removal of the layer improves thel qualit-y and clarity of the fina-l elements.

A satisfactory element for printing tW'o-e'ol'r components can be made by coating one side of a transparent nlm base with a gelatino-silver halide emulsion layer which is sensitive tol one portion of the visible spectrum, e.V g., blue, green. On such layer is coatedan aqueous solution of ay mobile orange-redcolor former and a Watersoluble, dilute alkali-insoluble colloid. The other side of the base is coated with a gelati-no-silver halide emulsion layer which is sensitive' to ay different portion of the visible spectrum', e: g.,

\ orange-red. On this layer there is coated an aqueous solution of a Water-soluble, dilute alkaliinsoluble colloid containing a blue-green, mobile color former. Appropriate color separation records are printed onto the respective' records and the element is color developed. The' outer layers are removed by washing in water. The silver and silver salts can then be removed by appropriate treatment, e'. g., bleaching with Farmers reducer. The resulting element contains dye iin-V ages in the original silver halide layers. The elements have good clarity, dyer density, and contrast. There Wes no evidence of signicant leaching of the color former into the developer solution on inspection oi the developer solutions. Such results indicate and a uni-directional travel of the intermediate.

When gelatin layers containing immobile or non-diffusing color formers are placed adjacent to gelatine-silver halide emulsion layers in like manner, quite different results are obtained. The' dye image is formed in the color former layer only. The images, moreover, have very low dye contrast. rEhe gelatin layer could not be removed by a simple Washing procedure.

Likewise when gelatin layers containing mobile or diffusing color formers Were coated on gelatino-silver halide emulsion layers and exposed and color processed in like manner different results were obtained. Dye images were formed in the silver halide emulsion layer and in the adjacent gelatin layer. The images were extremely at and the developer solution evidenced considerable contamination by color former which had leached from the film. r

In the preferred aspect of the invention the adjacent layers are composed of polyvinyl acetals of aromatic monoaldehydes having sulfonic acid or carboxylic acid groups, and mobile color formers. Suitable acetals of this type can be prepared from polyvinyl alcohols and substantially completely hydrolyzed polyvinyl esters and aldehyde carboxylic or sulfonic acids such as ortho-, meta-, and para-benzaldehyde sulfonic acid, acetaldehyde disulfonic acid, naphthaldehyde sulfonic acids, e. g., 1-naphthaldehyde-2-sulfonic acid, 1-naphthaldehyde-4-sulfonic acid, Z-naphthaldehyde--sulfonic acid, and the corresponding carboxylic acids, by condensation in the presence of mineral acids or acid salts after the mannerV described in German Patent No. 643,650. Such acetals are insoluble in aqueous alkaline photographic developer solutions containing 2% or more by weight of dissolved inorganic salts. The condensation should be carried out until the vinyl alcohol groups have been acetalized.

- Further the particular acetals just described possess high resistivity to alkaline developer solutions and appear to acquire an extremely hard surface when treated with them. Mobile or diffusing color formers which have been incorporated in this material and coated over a gelatin silver halide emulsion layer exhibit uni-directional dilusion into the emulsion layer. Only an insignificant quantity tends to diffuse into the alkaline developing solution. A cross-sectional study of the film shows that dye images are formed in the gelatin emulsion alone with no image formation in the adjacent resin-dye intermediate layer. This rapid uni-directional diffusion gives rise to strong contrasting dye images in the light-sensitive gelatin layer which is extremely important in color printing films.

VIhe invention will be further illustrated but is not intended to be limited by the following examples. The parts are by weight.

Example I A photographic element as illustrated in Fig. 1 of the drawing Was made by coating onto the respective sides ofa cellulose acetate iilm base l a gelatino-silver bromide iodide emulsion containing 15 grams of tartrazine per liter to form layer 2 having a coating weight of 80 mg./sq. decimeter, and to form similar layer 4. On layer 2 there was then coated a 5% aqueous dispersion containing the sodium salt of the polyvinyl alcohol acetal of ortho-benzaldehyde sulfonic acid containing 1 part of 3methyl-1-(meta-amino phenyl) --pyrazolone per parts of acetal to form thin layer 3. Similarly onto layer 4 there was coated layer 5 from a 5% aqueous solution of the aforesaid acetal containing 1 part of 2,4- dichloro-l-naphthol per 5 parts of acetal.

The film thus prepared was appropriately exposed to the green and red separation negatives of a set of three primary color separation negatives. The exposed element was then developed in N- diethylparaphenylenediamine.HCl grams 2.0 NazCOa do 30.0 KBr do 0.5 NazSOs d0 '7.0 Water to liter 1 and then washed, bleached in potassium ferricyanide and fixed in plain hypo. The outer polyvinyl acetal layers dissolved from the lm during the wash and left a two component element. The lm evidenced high speed and contrast, good color density and low stain. A satisfactory yellow component was applied by using a conventional imbibition matrix containing a yellow dye.

A similar lm can be made by substituting a yellow color former such as acetoacetanilide for either the blue-green or magenta color former. In addition to serving as a temporary binder for the color former, the acetal layers of the films operated as a very satisfactory anti-abrasion layer. All abrasions on the resin surface were, of course, removed in washing the layer oif.

Eiample II A photographic element is shown in Fig. 2 is 4made by coating a gelatino-silver bromide iodide emulsion onto a cellulose acetate iilm base 5 to form layer 'i having a coating weight of 80 mg. of silver halide per square decimeter. A layer 8 was coated onto the latter layer from a 3% aqeuous methyl cellulose (containing less than 10% methyl groups) solution containing 0.8 part of 3-methyl-1-(metaaminophenyl) 5 pyrazolone per 5 parts of methyl cellulose. The lm when exposed to an image and coloi` developed in a solution like that of Example I had a magenta image in layer 1. The film had good antiabrasion properties but was not as eilicient as that of Example I.

Example III The film illustrated in Fig. 3 is made by coating onto a baryta coated paper 9 a gelatino-silvei` bromide iodide emulsion layer l0 having a coating weight of 40 Ing/sq. decimeter. Onto this layer is coated a 11/2 aqueous solution of sodium alginate containing one gram of alpha-naphthol per l0 grams of sodium alginate to form layer l i Ihe lm was exposed to a negative and developed in a color developer solution of the type disclosed in Example I containing l part of aluminum chloride per liter of developer. A dye image remainder in layer l0 after removal of the silver and silver salts by bleaching in 3.5% potassium ferricyanide and fixing in plain hypo. The sodium alginate layer Il is readily removed by washing in water at any time after development. A source of strontium, barium or calcium ions, e. g., strontium nitrate, calcium chloride, calcium nitrate, can 'be substituted for the aluminum compound.

Example IV The iilm element shown in Fig. 4 is made in like manner by coating a cellulose acetate film base I2 with a iine grain gelatino-silver bromide iodide emulsion to a weight of 60 mg, of silver halide per square decimeter forming layer i3. On this layer is coated a 3% aqueous mixture of 5 parts of cellulose acetate-acid phthalate sodium salt and one part of gelatin, having incorporated HC1 grams 3.0 NazCOa (anhydrous) do ,30.0

do .25 NazSOa (anhydrous)v do 10.0 Water to 1iter 1 vyielded a blue-green image in layer i3. Layer I4 was removed readily in the wash after development. l

AContamination tests run on the developing solution showed an extremely low concentration ,of leached color former.

Example V A iilm element as vrillustrated in Fig. 5 of the drawing was made by preparing an aqueous emulsicm of silver halide in a completely hydrolyzed Vinyl acetate/ethylene interpolymer, as described in Example I 'of McQueen United States 4application Serial No. 528,945, filed March 31, 1944, now United States Patent 2,397,866, hardening it by treatment with formaldehyde or 'dimethylolurea. Hardening may be effected `by heating a solution containing 5 parts of the polymer with one part of dimethylolurea at 30 C. for three hours. The resulting dispersion or emulsion was then coated Von 'a casting wheel to a thickness 'of '0.0005 inch thick. A lm element I5 composed of the hardened polymer emulsion was formed. A 40 mg./'sq. decimeter layer it composed of the polyvinyl a'cetal of Example I having dispersed therein 1 gram of l-phenyl-B- methyl--pyrazolone per grams of lacetal was deposited on nlm l5. The element was exposed, color 'developed and processed, after the manner described in Example I, and yielded a magenta image lin the film l5. Layer I6 was easily removed during a Water washing step following development.

Example VII A cellulose acetate lm base Il as shown in Fig. 6 of the drawing was provided with an 80 mg. per sq. decimeter coating of a panchromatic 'gelatino-silver iodobromide emulsion layer I8. On this layer was deposited a 30 mg. Der sq. decimeter coating I9 of a mixture of 20 parts of sodium caseinate to one part of gelatin containing one gram ci acetoacetanilide per ve grams of mixed binder Vfrom an aqueous solution thereof. Exposure and color development of the resulting film, after the manner described in Example I, resulted after removal of the silver and silver salts of a yellow image being formed in layer I3. The film was not as efficient as those described above using synthetic hydroxyl polymer and cellulose derivative dispersione but was still useful for preparing dye images.

In place of the specific color formers described in the above examples, there may be used a large number of other" mobile color` formers. The utility of a particular color former of this type can be readily determined by incorporating a conventional amount of the intermediate in a gelatin silver halide emulsion layer on a lm base in ordinary illumination. One half of a strip of the film is immersed for ten minutes in a 5% sodium carbonate solution. After a short rinse, the complete strip is developed in a normal color developer. If the leached end is lighter in in- 6 tensi'ty than the unle'a'ch'ed end then the color former is mobile and will be operable in the process. Generally those which show considerable mobility are more satisfactory than those of only slight mobility for 'this type of process.

The expression color former as used herein has thewell-established meaning in the art and references to organic compounds which are capable of coupling with oxidized primary aromatic developing agents to form quinoneimine or azomethine dyes. Such compounds are also capable of condensation Aor coupling with Vdiazotized aromatic amines to form azo dyes.

Color formers usually contain as the active group a structure which may be represented by the formula:

Katar-Jaca where X is HO- or RHN- or an aliphatic or substituted aliphatic group, and n is 0 01 1. rIhe free or dangling valences may be, of course, satisfied by any of a large number of atoms or groups, e. g, hydrogen, halogen, carboxylic or sulfonic acid groups and their derivatives, fused rings, alkyl, aryl, alkoxy, a-ryloxy, etc. The hydrogen atom in the formula may be replaced by groups readily displaced in the coupling reaction, e. g., halogen atoms, carboxylic or sulionic acid groups. This group is found in the reactive methylene dye intermediates and in aromatic hydroxyl and amino compounds and includes the reactive ethenol, aminoethenyl, 4-hydroxyand 4amino-l,3butadienyl groups. These groups occur in phenols, naphthols, aromatic amines,

f acylacetamides, beta-ketoesters, pyrazolones,

have a hydrogen rendered mobile by the proxi- :mity of certain unsaturated groups, such as for example '-NOa and others. The CH2 group Yis vusually present between two such groups, for example, --COCH2CO-, GOOI-ECN, -'COCH2C=N-,

in a cyclic or acyclic system. The enol forms of these examples are and , yl Ho =oH-o=N respectively.

The reactive amino ethenyl group RI-IN-C=CH- occurs in aromatic amino compounds which couple in the ortho position.

The lc-hydroxyand 4aniino.1,3-butadienyl groups represented as occur in phenolic, naphtholic and aromatic amino compounds which couple in the para position.

In place of the gelatin which is used as a binding agent for the light-sensitive silver salts, there may be substituted other Water-permeable Yor hydrophilic colloids which are insoluble in photographic developing and xing, etc. solutions. VSuitable colloids include agar-agar, polyglycuronic acid, hydrophilic polymers, hydrophilic cellulose derivatives, e. g., ethyl cellulose, cellulose acetate containing to 25% of solubilizing groups, such as acid phthalate groups, etc.

The colloid silver halide emulsion layers may contain in addition to the light-sensitive silver halide, e. g., silver chlorides, silver-chloridebromide, silver-iodobromide, etc., various sensitizing dyes and other materials which are cornmon in emulsion layers. Such additional materials include fog inhibiting agents, emulsion hardeners, emulsion perservatives, etc.

An advantage of this invention resides in the fact that it provides new elements for color photography which utilize mobile color formers. Color ormers of this type do not give satisfactory results in gelatin layers espectially in multilayer photographic elements because such color formers migrate from layer to layer and into the processing solutions.

An additional advantage oi the novel elements resides in the fact that the silver halide layers are protected during exposure and processing. The outer protective layer can be effectively removed by a simple Washing operation. The color former-resin layer forms an effective antabrasion surface for the emulsion layer which is also meritorious.

As many widely different embodiments of this invention can be made Without departing from the spirit and scope thereof, it is to be understood that the invention is not to be limited except as defined by the claims.

What is claimed is:

1. A photographic element comprising a support, a light-sensitive colloid-silver halide emulsion layer superposed thereon bearing on its entire surface a dry outer layer of a water-soluble colloid Which is insoluble in aqueous alkaline developer solutions containing at least 2% by Weight of dissolved inorganic salts, said outer layer containing a mobile color former which is capable of coupling with oxidized `primary aromatic amino developing agents to form a dye taken from the group consisting of quinoneimine and azomethine dyes.

2. A photographic element comprising a support, a light-sensitive gelatino-silver halide emulsion layer superposed thereon bearing on its entire surface a dry outer layer of a Watersoluble colloid which is insoluble in aqueous alkaline developer solutions containing at least 2% by Weight of dissolved inorganic salts, said outer layer containing a mobile color former which is capable of coupling with oxidized primary aromatic amino developing agents to form a dye taken from the group consisting of quinoneimine and azomethine dyes.

3. A photographic element comprising a transparent support, a light-sensitive hydrophilic colloid-silver halide emulsion layer superposed thereon bearing on its entire surface a dry outer layer of a Water-soluble colloid which is insoluble in aqueous alkaline developer solutions containing at least 2% by Weight of dissolved inorganic salts, said outer layer containing a mobile color former which is capable of coupling with oxidized primary aromatic amino developing agents to form a dye taken from the group consisting of quinoneimine and azomethine dyes.

4. A photographic element comprising a transparent support, a light-sensitive gelatino-silver halide emulsion layer superposed thereon bearing on its entire surface a dry outer layer of a Watersoluble colloid which is insoluble in aqueous alkaline developer solutions containing at least 2% by weight of dissolved inorganic salts, said outer layer containing a mobile color former which is capable of coupling with oxidized primary aromatic amino developing agents to form a dye taken from the group consisting of quinoneimine and azomethine dyes.

5. A photographic element comprising a support, a light-sensitive hydrophilic colloid-silver halide emulsion layer superposed thereon bearing on its entire surface a dry outer layer composed of a polyvinyl acetal of an aromatic aldehyde containing an acid group taken from the class consisting of carboxylic acid and sulfonic acid groups, said acetal having intimately dispersed therethrough a mobile color former which is capable of coupling with oxidized primary aromatic amino developing agents to'form a dye taken from the group consisting of quinoneimine and azomethine dyes.

6. A photographic element comprising a transparent support, -a light-sensitive gelatino-silver halide emulsion layer superposed thereon bearing on its entire surface a dry outer layer composed of a polyvinyl acetal of an aromatic aldehyde containing a sulfonic acid group, said acetal having intimiately dispersed therethrough a mobile color former which is capable of coupling with oxidized primary aromatic amino developing agents to form a dye taken from the group consisting of quinoneimine and azomethine dyes.

'7. A photographic element comprising a transparent support having on each side thereof a light-sensitive colloid-silver halide emulsion layer superposed thereon bearing on its entire surface a dry outer layer of a water-soluble colloid which is insoluble in aqueous alkaline developer solutions containing at least 2% by Weight of dissolved inorganic salts, said outer layer containing a mobile color former which is capable of coupling with oxidized primary aromatic amino developing agents to form a. dye taken from the group consisting of quinoneimine and azomethine dyes.

8. A photographic element comprising a transparent support having on each side thereof a light-sensitive gelatino-silver emulsion layer superposed thereon bearing on its entire surface a dry outer layer o a water-soluble colloid which is insoluble in aqueous alkaline developer solutions containing at least 2% by weight of dissolved inorganie salts, said outer layer containing a mobile color former which is capable of coupling with oxidized primary aromatic amino developing agents to form a dye taken from the group consisting of quinoneimine and azomethine dyes.

9. A photographic element comprising a transparent support having on each side thereof a light-sensitive gelatine-silver halide emulsion layer superimposed thereon bearing on its entire surface a dry outer layer composed of a polyvinyl acetal of an aromatic aldehyde containing a sulfonic acid group, said acetal having dispersed therethrough a mobile color former 9 which is capable of coupling with oxidized primary aromatic amino developing agents to form a dye taken from the group consisting of quinoneimine and azomethine dyes.

10. The process which comprises exposed a Iphotographic element of the type defined in claim 1 to an object field, developing said element in a developer solution containing a primary aromatic amino developing agent, removing the silver and silver salts and Washing the out'er layer from the element at some stage after development.

11`.` A photographic element comprising a transparent support having a light-Sensitive hydrophilic 'colloid-silver halide emulsion layer superposed on at least one surface a layer composed of sodium-o-sulfobenzaldehyde acetal of polyvinyl alcohol coated on the entire surface of at least one of said emulsion layers, said acetal having intimately dispersed therethrough a 20 10 l mobile color former which is capable of coupling with oxidized primary aromatic amino color developing agents to form a dye taken from the group consisting of quinoneimine and azomethine dyes.

OTIS WILLARD MURRAY.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number' Name Date 1,905,438 Capstaff Apr. 25, 1933 1,954,337 Staud Apr. 10, 1934 1,966,330 Burwell July 10, 1934 2,159,600 Murray et al. May 23, 1939l 2,196,226 Murray et al. Apr. 9, 1940 2,323,246 Schneider et al. June 29, 1943 

1. A PHOTOGRAPHIC ELEMENT COMPRISING SUPPORT, A LIGHT-SENSITIVE COLLOID-SILVER HALIDE EMULSION LAYER SUPERPOSED THEREON BEARING ON ITS ENTIRE SURFCE A DRY OUTER LAYER OF A WATER-SOLUBLE COLLOID WHICH IS INSOLUBLE IN AQUEOUS ALKALINE DEVELOPER SOLUTIONS CONTAINING AT LEAST 2% BY WEIGHT OF DISSOLVED INORGANIC SALTS, SAID OUTER LAYER CONTAINING MOBILE COLOR FORMER WHICH IS CAPABLE OF COUPLING WITH OXIDIZED PRIMARY AROMATIC AMINO DEVELOPING AGENTS TO FORM A DYE TAKEN FROM THE GROUP CONSISTING OF QUINONEIMINE AND AZOMETHINE DYES. 